The present invention relates to an apparatus and a method for thermosoling a dye carried by a textile material.
In thermosol (also known as thermofixation or thermosol fixation) treatment of textiles, dyestuffs applied to the textile are heated for dispersal and penetration of the dyestuffs to permanently attach the dye to the fibers of the textiles. It is known to apply the required heat in several ways, such as by radiation and by using steam. The heat applied to the textile and the attached dyestuffs causes the dyestuffs to diffuse into the polymer of the textile so that the dyestuffs are thoroughly bonded to the fibers. An example of such a method is described in international patent application WO 95/19266.
In U.S. Pat. No. 3,973,417, it is disclosed to heat the dyestuffs using infrared radiation. A problem of this known method is that it is not very efficient in terms of the amount of dye required to achieve a given printing density. The percentage of unused dyes, i.e. dyestuffs that do not bond with the fibers and have to be removed before the textile can be used without staining under normal conditions is substantial.
For this reason, the treated textile is washed after having been subjected to a heat treatment. This washing step increases manufacturing costs and the washing water needs to or at least should preferably be cleaned before it can be drained to waste. Even if the water is cleaned, the use of excess dyestuff, the water necessary for washing and the energy consumed in the course of washing and drying cause substantial amounts of pollution.
Moreover, this known form of thermosol treatment is unsuitable for treating textiles carrying a surface printing consisting of only small amounts of dye, such as textiles on which patterns have been printed by using an ink jet printer, since that would generally result in unacceptably low final printing densities. For that reason thermofixation of surface printed patterns onto a textile material has thus far usually been carried out by printing onto a substrate and transferring the pattern onto the textile by pressing the printed face of the substrate against the textile and simultaneously applying heat. However, transfer printing is laborious and also entails the consumption of large amounts of substrate which has to be discarded.
It is an object of the invention to make the thermosoling treatment of printed textiles more efficient in terms of the amount of dye on the textile necessary to achieve given printing densities and to reduce the extent to which staining is caused, so that, at least in general, washing of the treated textile can be dispensed with.
According to the present invention, this object is achieved by providing an apparatus for thermosol treatment of surface printed textile, with a transport structure for transporting a web of surface printed textile through a treatment space in its longitudinal direction, and at least one heat source arranged for emitting heat in the treatment space, the apparatus being adapted for generating a pressure drop over the web from a first side of the web to an opposite, second side of the web for entraining sublimated ink on the first side of the web back to the web.
According to the present invention, this object is also achieved by including the following steps in a method for thermosol treatment of surface printed textiles: providing a web of surface printed textile carrying a surface print on a printed face thereof, the printed face facing to a first side of the web, transporting the web along a trajectory extending through a treatment space, heating at least a portion of the web in the treatment space and generating a pressure drop over the web from the first side of the web to an opposite, second side of the web for entraining sublimated ink on the first side of the web back to the web.
The foregoing and other objects, features and effects of the present invention are further described in and may be more readily understood from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings.